Using CRC32 algorithm to hash string at compile-time

Basically I want in my code to be able to do this:

 Engine.getById(WSID('some-id'));

Which should get transformed by

 Engine.getById('1a61bc96');

just before being compiled into asm. So at compile-time.

This is my try

constexpr int WSID(const char* str) {
    boost::crc_32_type result;
    result.process_bytes(str,sizeof(str));
    return result.checksum();
}

But I get this when trying to compile with MSVC 18 (CTP November 2013)

error C3249: illegal statement or sub-expression for 'constexpr' function

How can I get the WSID function, using this way or any, as long as it is done during compile time?

Tried this: Compile time string hashing

 warning C4592: 'crc32': 'constexpr' call evaluation failed; function will be called at run-time